Dirk Nowitzki of the Dallas Mavericks, underwent arthroscopic knee surgery this week, meaning he will be out for 6-8 weeks.

Nowitzki, 34, has been in the NBA for 14 seasons and this is the first time he has gone under the knife in his career. Nowitzki wrote on his Twitter account (@swish41) on Saturday, "Thanks for all the kind words and thoughts and prayers. Means a lot to me. I hope to be back out there pretty soon. Will keep u posted."

Dirk has had his knee drained twice this pre-season, with the swelling returning to the knee in both cases. The Dallas team doctors then decided that it was best to have surgery on it sooner, rather than later.

The Mavericks might struggle without their big man for the first few weeks of the NBA season, as he's been their leader on the court for many years. Nowitzki is amongst a few NBA stars who are going to be sitting out the start of this season due to recent injury problems, with the likes of Kevin Love out who is also due to miss 6-8 weeks with a broken hand.